This invention relates to a positive end expiratory pressure valve (referred to as a PEEP valve). In the current art, PEEP valves usually include a hollow cylinder or port providing a gas flow path for exhalation gas from a patient to which the PEEP valve is connected. The PEEP valve requires an adjustable exhalation gas pressure before it releases exhalation gasses into the atmosphere, thereby maintaining pressure in a patient's lungs.
Numerous devices are known to the art which provide flow paths for gasses such as air, oxygen, anesthesia gas, and the like. Numerous medical apparatus are also known to the art which provide a gas flow path for exhalation gas from a patient's lungs such as air, oxygen, anesthesia gas, etc.
PEEP valves, as known to the art, are used to maintain a predetermined pressure level in the lungs of a patient who is being ventilated with oxygen, air or anesthetized by an anesthesia gas. Typical PEEP valves includes a spring biased relief valve which remains closed and prevents the patient from exhaling until the pressure of the patient's exhalation gas exceeds the force of the spring after which the valve opens and the patient's exhalation gas is exhausted through a exit port on the PEEP valve and into the atmosphere. As the patient continues to exhale, the pressure of the exhalation gas decreases until it reaches the force set by the spring biased relief valve and the valve closes thereby preventing the further flow of exhalation gas from the patient's lungs. The gas remaining in the patient's lungs which otherwise would be exhaled, remains in the patient's lungs at a pressure equal to, or at least substantially equal to, the pressure setting of the spring. It is advantageous for a patient being ventilated or anesthetized to have at least some pressure remaining in their lungs and to prevent the patient's lungs from being totally evacuated during exhalation. The maintenance of such gas pressure is believed to have a salutary effect on the sacks or alveoli of the patient's lungs.
FIG. 1 of U.S. Pat. No. 6,135,108 to Richard Hoenig shows a patient being ventilated by air or oxygen from a suitable source. This patent is hereby included by reference. Gas enters the flowmeter, flows through the heated humidifier, through tubing (12), through a T-piece, and into the endotracheal tube with which the patient is intubated. When the patient exhales, the exhalation gas from the patient's lungs flows through the endotracheal tube, the T-piece and into the PEEP valve. When pressure exceeds the spring force of the PEEP valve, the patient's exhalation gas exits through the PEEP valve's exit port and into the ambient air in the patient's room.
Existing PEEP valves allow exhalation gasses to exit into the atmosphere around the patient. In many hospital situations, the patient has a communicable disease ranging from the common cold to bacterial pneumonia. As the patient exhales, pathogens, microbes or microorganisms are released, for example, in aerosolized droplets. These pathogens exit the PEEP valve exit port when the patient exhales as described above. Many pathogens will cause an infectious disease in a healthy adult, but those pathogens and a host of other pathogens cause an infectious disease in a person with depressed resistance (e.g. a patient suffering from another disease such as HIV or cancer). The later are classified as opportunistic pathogens. Being that many other patients in a hospital or even in the same room as the person using the PEEP valve potentially have depressed resistance; they are more susceptible to acquiring such a disease from the person using the PEEP valve. Likewise, for certain diseases and pathogens, caretakers are also susceptible to such microbes and pathogens.
In the past, recognizing the dangers of allowing such pathogens to leave the patient's lungs and into the atmosphere, medical facilities have attached filters between the PEEP valve and the patient airway. This reduces pathogen emission into the atmosphere, but requires a separate filter device inserted into the flow path. A separate filter device adds costs for the housing and connections, creates a larger, more cumbersome connection and increases the chances of a disconnected flow path.
What is needed is a PEEP valve with integral filter that prevents or reduces the emission of pathogens into the air surrounding the patient using such device.